Containers or vessels of this kind, which can be manufactured from elastic plastic materials by the injection moulding method, in particular, are widely used because of their inexpensive manufacture and their low weight. They are eminently suited to the stocking, storage and transport of pourable goods in liquid or also granulated form in handy packagings, without having to accept major restrictions as regards weight or shape as a result of the container itself. Moreover, the contents of the container need not be consumed in a single operation, as the container can be re-sealed with a cover, meaning that the contents can still be used after opening the container once or several times.
However, this initially highly positive feature entails the disadvantage that, as a result, the container must in some way be provided with an indication for the user or buyer to show whether or not an opening procedure has already taken place at some time; in other words, the intactness or original condition of the container should preferably be apparent even at only a fleeting glance.
In general, the removal of a cover from a container is facilitated by raising an area of the cover, for which purpose an aid of the nature of a tongue-like element is used, such as known from U.S. Pat. No. 3,753,512, for example.
A container of the kind mentioned in the opening paragraph is known, for example, from EP 0 565 967 B2, which describes a container to whose container edge a tongue-like element is connected that raises the cover as a result of a pivoting movement away from a starting position. In this context, at least one of the face edges of the ends of a fastening flange is supposed to be connected to the associated edge of the tongue-like element via thin-walled, plastic webs or a plastic film that are easy to tear off. A tamper-proof seal of this kind is disadvantageous because, being easy to tear off, these webs can also be detached unintentionally, thus indicating opening that has not in fact taken place. In addition, the intended indication of previous opening is also not necessarily unequivocal. If, for example, the cover is placed back onto the container after being raised, and the tongue-like element returned to its starting position, it may be that the webs still remaining on at least one end of the edges more likely suggest that the container has not yet been opened.
On a container disclosed in EP 1 052 183 A1, a tongue-like element connected to the container likewise serves to raise the cover. When in its starting position, sections of the tongue-like element are overlapped, without engaging, by one or more web-like elements, these elements being designed to break open or be deformed when the tongue-like element is moved away from its starting position in order to open the container. However, it can happen in this context that, after subsequent re-closing, when the tongue-like element is again in its starting position, the element or elements is or are likewise back in their original position, i.e. come to rest on the tongue-like element, meaning that indication of the previous opening of the container is not guaranteed. At the same time, the web-like elements overlapping the tongue-like element are also susceptible to being damaged or torn off, e.g. during transport, this again meaning that opening of the container would be indicated without actually having taken place.